Image guided minimally invasive therapies allow rapid and effective treatments with low blood loss. But it depends heavily on the imaging system. C-arm CT imaging provides conventional two dimensional (2D) and 3D volumetric imaging for intra-procedural navigation and assessment. These systems, based on flat panel detectors (FPD) however, impose trade-offs between spatial resolution, field of view (FOV), frame rate, and image noise. A novel detector with a mercuric iodide coated Complimentary Metal Oxide Semiconductor (CMOS) chip is expected to address these problems. It will allow large FOV imaging with 120 micron pixels at 120 frames/s and only 500e rms noise. The proposal aims to optimize its design and performance for Carm CT imaging. This will be particularly useful in stroke treatment. The staged development of the CMOS detector will involve theoretical modeling of the imaging chain to predict its performance. The imaging characteristics of panels prepared by our collaborator will be tested on a table-top CT system and compared with these predictions. Any image degradation processes will be identified and the detector design will be modified. Panels with increasing imaging area built from tiled chips (10.5cmx11cm and 22cmx28cm) will be examined and optimized. Fluoroscopic, angographic and perfusion CT imaging will be considered and compared with the performance of an FPD. Opportunities for reduction in dose will be evaluated. Eventually two 22cmx28cm detectors will be implemented on a biplane C-arm gantry. In vivo imaging of flow and perfusion pre and post occlusion in a canine stroke model will be conducted and compared with results from a clinical CT scan. An imaging protocol that utilizes the maximum potential of the detector will be developed. The technical innovations of the proposal lie in the ability to use this unique large area high speed detector for extracting maximum 2D, and particularly, 3D information for aiding minimally invasive procedures. RELEVANCE OF RESEARCH: This proposal aims to improve image guided interventions which are growing in importance since they allow quicker reovery and reduce costs compared to conventional surgeries. This will be achieved by developing a camera for x-ray detection that will allow CATscan-like imaging along with viewing in realtime the manipulation of insturments in the brain for stroke treatment.